Bidirectional biomechanical prosthetic full finger configured for abduction and adduction with MCP pivot and multiple-finger ring

ABSTRACT

The disclosure provides apparatus and methods of use pertaining to a bidirectional biomechanical prosthetic finger assembly. One embodiment includes a metacarpophalangeal (MCP) pivot configured for swivelable attachment to a hand of a user, a distal coupler, and an articulation assembly rotatively coupled therebetween. A multiple-finger ring configured to receive a user&#39;s residual finger and at least one adjacent finger is disposed upon the articulation assembly, and may be adjusted to a target location based on a length of the residual finger. The articulation assembly is configured to utilize vertical movements of the residual and/or adjacent finger(s) within the multiple-finger ring to articulate the distal coupler within a plane parallel to an x-z plane, and the MCP pivot is configured to utilize lateral movements of the residual finger within the ring to articulate the distal coupler within a plane parallel to an x-y plane. Other embodiments are also disclosed.

REFERENCE TO PENDING PRIOR PATENT APPLICATIONS

The application claims the benefit under 35 U.S.C. 119 (e) of U.S.Provisional Patent Application Nos. 62/162,524, filed May 15, 2015 byRobert Thompson and Jon Bengtsson for “BIO-MECHANICAL PROSTHETIC FULLFINGER CONFIGURED FOR ARTICULATION WITH A DOUBLE RING,” 62/162,516,filed May 15, 2015 by Jon Bengtsson and Robert Thompson for“BIO-MECHANICAL PROSTHETIC FULL FINGER CONFIGURED FOR ABDUCTION ANDADDUCTION WITH MCP PIVOT,” and 62/209,836, filed Aug. 25, 2015 by RobertThompson JR., Jon Bengtsson, Anthony Charles Peto, Sydney Tye Minnis,Eric Dennis Klumper, and Bradley Arthur Crittenden for “BIO-MECHANICALPROSTHETIC FULL FINGER CONFIGURED FOR ABDUCTION AND ADDUCTION WITH MCPPIVOT,” all of which patent applications are hereby incorporated hereinby reference.

BACKGROUND

If a person loses finger mobility, finger functionality, or all or asegment of his or her physical finger, the result is impairedperformance of the hand. Having an amputated or minimally functioningfinger (e.g., due to nerve damage, excessive scar tissue, neurologicaldamage or disorders, or other bone or musculature dysfunctionalities)inhibits the person from performing some of the most basic tasks. Forexample, with one or more dysfunctional fingers, the task of typing on acomputer keyboard or dialing on a telephone becomes significantly moredifficult. These types of tasks require precise actions that onlyfingers are able to offer.

Not only do fingers allow for the performance of precise physicalactions, they also provide an increased ability to grip or handle items.While holding an item in the hand, the weight of the item is dispersedthrough all of a user's fingers. By varying the force used by eachfinger on the holder's hand, the holder is able to manipulate the itemin a myriad of ways. However, if the holder is missing all or even partof a single finger/digit, or if a digit is present but nonfunctioning,this freedom of manipulation and the number of degrees through which theholder can manipulate the item is drastically decreased.

A primary category of current prosthetic finger solutions is designed tobe worn passively and offer a realistic look. These solutions providelittle to no functionality and do not enable the owner to restorefunctionality to his or her hand. Other prosthetics offer the user somelevel of restored functionality, but are complex in design and eitherdepend on a motorized actuator to articulate the prosthetic orspecifically claim to anchor to the user's hand through a “stationarymatrix,” which may, for instance, include a bracket that slips over theuser's residual finger stub. These prosthetics, while perhaps betterthan going without, are impractical in that they often require anexternal power source and/or can be limited in functionality and bothbulky and unwieldy for the user to manage. Still other prostheticfingers and/or braces are body-powered but lack the design flexibilitynecessary to accommodate any length of residual finger (e.g., all orpartially amputated and varying degrees of amputation) while providingmaximum dexterity, grip strength, and finger articulation in anattractive, low-profile device.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key aspects oressential aspects of the claimed subject matter. Moreover, this Summaryis not intended for use as an aid in determining the scope of theclaimed subject matter.

One embodiment provides a bidirectional biomechanical finger assemblyfor a user's residual finger. The finger assembly includes ametacarpophalangeal (MCP) pivot, a distal coupler, and an articulationassembly rotatively coupled between the MCP pivot and the distalcoupler. The articulation assembly includes (1) an adjustable ringtendon having a distal end, a proximal end, and a longitudinaladjustment mechanism disposed therebetween, the proximal end rotativelycoupled with the MCP pivot; (2) a multiple-finger ring configured toreceive and retain the residual finger and at least one adjacent finger,the multiple-finger ring selectively disposed upon the adjustable ringtendon at a target location along the longitudinal adjustment mechanism;(3) a proximal coupler; and (4) a distal rocker. The proximal couplerand the distal rocker are rotatively suspended between a proximalcoordinated pivot point anchored upon the adjustable ring tendon and adistal coordinated pivot point anchored upon the distal coupler. Inaddition, the articulation assembly is configured to utilize verticalmovements of at least one of the residual finger and the at least oneadjacent finger within the multiple-finger ring to articulate the distalcoupler within a plane parallel to an x-z plane and about one or moreaxes parallel to a y axis, and the MCP pivot is configured to utilizelateral movements of at least one of the residual finger and the atleast one adjacent finger within the multiple-finger ring to articulatethe distal coupler within a plane parallel to an x-y plane and about anaxis parallel to a z axis.

Another embodiment provides a bidirectional biomechanically drivenprosthetic finger. The prosthetic finger includes an MCP pivot forattachment to a hand of a user, the MCP pivot having an articulationjoint configured to rotate the MCP pivot relative to the hand within aplane parallel to an x-y plane and about an axis parallel to a z axis.The prosthetic finger also includes a distal coupler and an articulationassembly rotatively coupled between the MCP pivot and the distalcoupler, the articulation assembly configured to articulate relative tothe hand within a plane parallel to an x-z plane and about one or moreaxes parallel to a y axis. The articulation assembly comprises (1) aproximal coupler rotatively coupled with the distal coupler via a firsthinged connection; (2) an adjustable ring tendon having a proximal end,a distal end, and a multiple-finger ring disposed thereon, themultiple-finger ring configured to anchor onto a residual finger and atleast one adjacent finger of the user and slidably adjustable betweenthe proximal and distal ends of the adjustable ring tendon; and (3) adistal rocker extending between the distal coupler and the adjustablering tendon, the distal rocker having a distal end and a proximal end.The adjustable ring tendon is rotatively coupled with the proximalcoupler via a third hinged connection, and the first and third hingedconnections define a midline relative to the z axis. The distal end ofthe distal rocker rotatively couples with the distal coupler via asecond hinged connection located below the midline, and the proximal endof the distal rocker rotatively couples with the adjustable ring tendonvia a fourth hinged connection located above the midline.

Yet another embodiment provides a method of biomechanically operating abidirectional prosthetic finger having a hand strap, an MCP pivotaffixed to the hand strap, a distal coupler, and an adjustablearticulation assembly rotatively coupled between the MCP pivot and thedistal coupler. The adjustable articulation assembly includes amultiple-finger ring configured to receive a residual finger and atleast one adjacent finger of a user's hand. The method includes (1)assessing a length of the residual finger; (2) adjusting themultiple-finger ring to a target location along the adjustablearticulation assembly, the target location based on the length of theresidual finger; (3) securing the ring at the target location; (4)sliding the prosthetic finger onto the residual finger such that themultiple-finger ring encircles the residual finger and the at least oneadjacent finger, and the MCP pivot aligns with an MCP joint of the user;(5) securing the hand strap about the hand; (6) moving one of theresidual finger and the at least one adjacent finger vertically withinthe multiple-finger ring, thereby causing the adjustable articulationassembly together with the distal coupler to articulate within a planeparallel to an x-z plane and about one or more axes parallel to a y axisin a manner that emulates a finger's natural articulation; and (7)moving one of the residual finger and the at least one adjacent fingerlaterally within the ring, thereby causing the MCP pivot to rotate aboutan axis parallel to a z axis within a plane parallel to an x-y plane,such that the articulation assembly together with the distal couplerabduct away from a midline of the hand and adduct toward the midline ofthe hand.

Other embodiments are also disclosed.

Additional objects, advantages and novel features of the technology willbe set forth in part in the description which follows, and in part willbecome more apparent to those skilled in the art upon examination of thefollowing, or may be learned from practice of the technology.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention,including the preferred embodiment, are described with reference to thefollowing figures, wherein like reference numerals refer to like partsthroughout the various views unless otherwise specified. Illustrativeembodiments of the invention are illustrated in the drawings, in which:

FIG. 1 illustrates a perspective view of one embodiment of abidirectional biomechanically driven prosthetic finger, as pivotallycoupled with a hand strap;

FIG. 2 illustrates a perspective view of a metacarpophalangeal (MCP)pivot of the prosthetic finger of FIG. 1;

FIG. 3 illustrates a perspective view of an articulation assembly of theprosthetic finger of FIG. 1, as coupled between the MCP pivot of FIG. 2and a distal coupler;

FIG. 4 illustrates a perspective view of the distal coupler of FIG. 3;

FIG. 5 illustrates a top view of another embodiment of a bidirectionalbiomechanically driven prosthetic finger;

FIG. 6 illustrates a side view of the prosthetic finger of FIG. 5,disposed above a hand of a user and in an extended position;

FIG. 7 illustrates a side view of the prosthetic finger of FIG. 5 in aretracted or curled position;

FIG. 8 illustrates a top view of another embodiment of a bidirectionalbiomechanically driven prosthetic finger;

FIG. 9 illustrates a front perspective view of the prosthetic finger ofFIG. 8 in a curled position;

FIG. 10 illustrates a rear perspective view of the prosthetic finger ofFIG. 8 in a curled position;

FIG. 11 provides a flow chart depicting an exemplary method of operatingthe prosthetic finger of FIGS. 8-10;

FIG. 12 illustrates a top view of another embodiment of a bidirectionalbiomechanically driven prosthetic finger featuring a multiple-fingerring;

FIG. 13 illustrates a front perspective view of the prosthetic finger ofFIG. 12; and

FIG. 14 illustrates a rear perspective view of the prosthetic finger ofFIG. 12.

DETAILED DESCRIPTION

Embodiments are described more fully below in sufficient detail toenable those skilled in the art to practice the system and method.However, embodiments may be implemented in many different forms andshould not be construed as being limited to the embodiments set forthherein. The following detailed description is, therefore, not to betaken in a limiting sense.

Various embodiments disclosed herein relate to a custom-designed,self-contained, bidirectional, biomechanically driven prosthetic fingerassembly that can be fitted for a user with an amputated fingertip orfinger segment. The streamlined and sophisticated design allows for apatient with any level of residual finger to utilize a mechanicalprosthetic finger that mimics both the vertical and lateral motions andfunctionalities of a real finger. The natural movement of the prostheticfinger assembly allows users to regain maximum control of the flexion,extension, abduction, and adduction movements of a fully functioningfinger and fingertip and is designed to articulate in a realistic,natural manner in response to movement in the user's own residual fingerand/or adjacent fingers.

Embodiments described herein include a ring that is configured toreceive and retain a user's residual finger and/or adjacent fingersalong with an adjustable ring tendon, both discussed in detail below.The ring and adjustable ring tendon allow the biomechanical prostheticfinger to anchor to any length of residual finger, including anamputation of a fingertip or one or more finger segments, whileproviding the individual user with maximum fit and use flexibility,dexterity, grip strength, and bidirectional articulation. As a result,the prosthetic finger offers patients experiencing loss of finger/digitfunction, as well as partial digit amputees, a functional solution thateases the transition back into daily activities, no matter howintricate.

To facilitate explanation of the movement of the bidirectionalprosthetic finger discussed herein, relative vertical and lateralmovements of the components of the prosthetic finger embodimentsdiscussed below are explained in relation to three axes—an x axis, a yaxis, and a z axis—initially defined in FIG. 1. These three axisinherently define two relevant planes of movement—an x-y plane and anx-z plane.

Turing to the exemplary embodiments detailed in the figures, FIG. 1illustrates a perspective view of one embodiment of a bidirectional andbiomechanically driven prosthetic finger 100. In this embodiment,prosthetic finger 100 may include an eccentric metacarpophalangeal (MCP)pivot 102 configured to attach to a user's hand via a hand strap 104adapted to attach about a back of a user's hand (not shown). MCP pivot102 may include an anchor plate 106 ₂, selected from a number of anchorplates 106 ₁₋₄ that each align with a different MCP joint andcorresponding finger of the user, as shown in further detail in FIG. 2.In one embodiment, anchor plates 106 ₁₋₄ may be mounted directly uponhand strap 104, or they may be incorporated within or mounted upon astrap platform 108 to provide an appropriate alignment and/or depth withthe rest of prosthetic finger 100.

MCP pivot 102 may also include a frame 110. At its proximal end, frame110 may be rotationally coupled with anchor plate 106 ₂ via anarticulation joint 112. Articulation joint 112 may be a pin, a screw, orany other appropriate fastener that joins anchor plate 106 ₂ and frame110 such that frame 110 revolves relative to anchor plate 106 ₂ about anaxis parallel to the z axis. At its distal end, frame 110 may berotationally or hingedly coupled with an articulation assembly 114 (FIG.1).

FIG. 3 illustrates a perspective view of articulation assembly 114, asrotatively coupled between eccentric MCP joint 102 and a distal coupler116. In this embodiment, articulation assembly 114 may include aproximal rocker 118 having a proximal end 120 and a distal end 122thereof. Proximal end 120 of proximal rocker 118 may rotatively couplewith frame 110 via a hinged connection 124, and distal end 122 ofproximal rocker 118 may rotatively couple with distal coupler 116 via ahinged connection 126.

Articulation assembly 114 may also include an adjustable ring tendon128. Adjustable ring tendon 128 may have a proximal end 130 and a distalend 132. In this embodiment, proximal end 130 of adjustable ring tendon128 may rotatively couple with frame 110 via a hinged connection 134.Distal end 132 of adjustable ring tendon 128 may rotatively couple withdistal coupler 116 via a hinged connection 136.

In one embodiment, a ring 138 may be disposed upon adjustable ringtendon 128. Ring 138 may be configured to concentrically receive andretain the user's residual finger and may be formed of any appropriatemetal and/or plastic material. Ring 138 may incorporate a siliconeportion or portions for improved grip, comfort, and serviceability.These silicone portions may reside along a lower portion of ring 128and/or they may be incorporated along natural pressure points betweenthe finger and ring 128, such as at the top of the proximal phalanxbone.

Ring 138 may be adjusted along the length of adjustable ring tendon 128by sliding ring 138 along a longitudinal adjustment mechanism disposedwithin tendon 128. In this embodiment, the longitudinal adjustmentmechanism may be a longitudinal adjustment channel 140 formed withintendon 128. To adjust ring 138, a user may simply slide ring 138 along alength of channel 140 before securing ring, via a screw 142 or any otherappropriate fastener, to tendon 128 at a target location 144 alongchannel 140. Target location 144 may be based on a length of the user'sresidual finger and result in an alignment of MCP pivot 102 above/overthe user's MCP joint when the user's finger is retained within ring 138.Longitudinal adjustment channel 140 may have any appropriate lengthalong adjustable ring tendon 128. Further, the longitudinal adjustmentmechanism may take any appropriate size, shape, type, and/orconfiguration. For example, in an alternate embodiment, the longitudinaladjustment mechanism may be formed from a number of longitudinaladjustment holes disposed along the length of longitudinal adjustmenttendon 128.

FIG. 4 illustrates a perspective view of distal coupler 116, asrotatively coupled with a proximal end of articulation assembly 114. Asdiscussed above, distal coupler 116 may rotatively couple witharticulation assembly 114 via hinged connections 126 and 136. Distalcoupler 116 may include a tip pad 146. Tip pad 146 may be formed from asoft-textured silicone or other material that mimics the texture of areal finger. This aids with gripping and provides a softer touch. In oneembodiment, a touchscreen mechanism (not shown) may be provided to allowthe user to use prosthetic finger 100 to operate capacitivetouchscreens, which react to the body's natural current. The touchscreenmechanism allows the user to direct his or her own body current throughdistal coupler 116.

In this embodiment, distal coupler 116 may include a distalinterphalangeal (DIP) adjustment connector 148. DIP adjustment connector148 may be a screw or another appropriate fastener that allows distalcoupler 116 to be adjusted through 360 degrees of rotation, limited onlyby interference with other components of prosthetic finger 100. DIPadjustment connector 148 may be tightened at any desired angle, lendingdistal coupler 116 infinite adjustment options within a full range offeasible and/or desirable fingertip angles.

As discussed above and returning to FIG. 1, articulation assembly 114and distal coupler 116 are designed for bidirectional articulation.Specifically, assembly 114 and distal coupler 116 may rotate laterallyrelative to MCP pivot 102 via articulation joint 112, providingprosthetic finger 100 with a first direction of movement about an axisparallel to the z axis and within a plane parallel to the x-y plane.Hinged connections 124 and 134, which rotatively couple articulationassembly 114 to MCP pivot 102, as well as hinged connections 126 and136, which rotatively couple articulation assembly 114 with distalcoupler 116, provide a second, vertical direction of movement about axesparallel to the y axis and within planes parallel to the x-z plane. As aresult, the user may achieve more lifelike movements of distal coupler116 that emulate the natural articulation of a finger by moving his orher residual finger laterally (e.g., adducting and/or abducting theresidual finger) within ring 138 to actuate finger 100 in the firstdirection, and by moving his or her residual finger vertically withinring 138 to actuate finger 100 in the second direction, therebyachieving both lateral and vertical articulation of distal coupler 116.

FIGS. 5-7 illustrate respective top, side-extended, and side-curled(i.e., retracted) views of another exemplary embodiment of abidirectional and biomechanically driven prosthetic finger 200. In oneembodiment, prosthetic finger 200 may include an eccentric MCP pivot 202configured to attach to a user's hand via a hand strap (not shown)adapted to attach about a back of a user's hand. MCP pivot 202 mayinclude an anchor plate 206 designed to align with aselect/corresponding residual finger of the user. In one embodiment,anchor plate 206 may be mounted directly upon the hand strap via anyreasonable and/or appropriate means (e.g., sewn, riveted, adhered,etc.). In another embodiment, the hand strap and anchor plate 206 may bemolded or otherwise manufactured as a single piece.

MCP pivot 202 may also include a frame 210. At its proximal end, frame210 may be rotationally coupled with anchor plate 206 via anarticulation joint 212 adapted for positioning above the user's MCPjoint. Articulation joint 212 may be a pin, a screw, or any otherappropriate fastener that joins anchor plate 206 and frame 210 such thatframe 210 revolves relative to anchor plate 206 about an axis parallelto the z axis. At its distal end, frame 210 may be rotationally orhingedly coupled with an articulation assembly 214 that is rotativelycoupled between MCP joint 202 and a distal coupler 216.

In further detail and in this embodiment, articulation assembly 214 mayinclude a two-piece, mirror-image proximal rocker 218 having a proximalend 220 and a distal end 222. Proximal end 220 of proximal rocker 218may rotatively couple with frame 210 via a hinged connection formed oftwo mirror-image hinged connections 224. Distal end 222 of proximalrocker 218 may rotatively couple with distal coupler 216 via a hingedconnection formed of two mirror-image hinged connections 226.

Articulation assembly 214 may also include an adjustable ring tendon228. Adjustable ring tendon 228 may have a proximal end 230 and a distalend 232. In this embodiment, proximal end 230 of adjustable ring tendon228 may rotatively couple with frame 210 via a hinged connection 234.Distal end 232 of adjustable ring tendon 228 may rotatively couple withdistal coupler 216 via a hinged connection 236.

In one embodiment, a ring 238 may be disposed upon adjustable ringtendon 228. Ring 238 may be configured to receive and retain the user'sresidual finger and may be formed of any appropriate metal and/orplastic material. As discussed above in relation to ring 138, ring 238may incorporate a silicone portion or portions for improved grip,comfort, and serviceability. These silicone portions may reside along alower portion of ring 238 and/or they may be incorporated along naturalpressure points between the finger and ring 238, such as at the top ofthe proximal phalanx bone.

Ring 238 may be adjusted along the length of adjustable ring tendon 228by sliding ring 238 along a longitudinal adjustment mechanism formedwithin tendon 228. In this embodiment, the longitudinal adjustmentmechanism may be a longitudinal adjustment channel 240 formed withintendon 228. To adjust, a user may slide ring 238 along a length ofchannel 240 before securing ring 238, via a screw 242 or any otherappropriate fastener, to tendon 228 at a target location 244 alongchannel 240. Target location 244 may be based on a length of the user'sresidual finger and result in an alignment of MCP pivot 202 above/overthe user's MCP joint when the user's finger is retained within ring 238,as shown in FIG. 6. Longitudinal adjustment channel 240 may have anyappropriate length. The longitudinal adjustment mechanism may take anyappropriate size, shape, type, and/or configuration. For example, inother embodiments, the longitudinal adjustment mechanism may be a numberof longitudinal adjustment holes disposed along the length oflongitudinal adjustment tendon 228 or may be a retention ridgeincorporated into tendon 228 and designed to engage with a clamp orother securement device incorporated into ring 238.

As discussed above, distal coupler 216 may rotatively couple toarticulation assembly 214 via hinged connections 226 and 236. Distalcoupler 216 may include a tip pad 246. Tip pad 246 may be formed from asoft-textured silicone or other material that mimics the texture of areal finger and with gripping and provides a softer touch. Oneembodiment of distal coupler 216 may also include a nail 217, whichmimics a natural edged fingernail that may provide scratching andpeeling functionalities as well as assist with fine-object manipulation.

Like articulation assembly 114 of prosthetic finger 100, articulationassembly 214 and distal coupler 216 of prosthetic finger 200 aredesigned for bidirectional articulation. Specifically, articulationassembly 214 and distal coupler 216 may rotate laterally relative to thehand via articulation joint 212 of MCP pivot 202, providing prostheticfinger 200 with a first direction of movement about an axis parallel tothe z axis and within a plane parallel to the x-y plane. This lateralmovement is denoted by arrow A, shown in FIG. 5.

A second, vertical direction of movement is denoted by arrow B, shown inFIGS. 6 and 7. FIG. 6 depicts prosthetic finger 200, as disposed above ahand 205 of a user, in an extended position 250. FIG. 7 depicts theprosthetic finger 200 in a retracted or curled position 252.Specifically, hinged connections 224 and 234, which rotatively couplearticulation assembly 214 with frame 210 of MCP pivot 202, as well ashinged connections 226 and 236, which rotatively couple articulationassembly 214 with distal coupler 216, provide multiple rotationalconnections for movement about numerous axes parallel to the y axis andwithin planes parallel to the x-z plane. As a result, the user mayachieve more lifelike movements of distal coupler 216 that emulate thenatural articulation of a finger by moving his or her residual fingerlaterally (e.g., adducting and/or abducting the residual finger) withinring 238, and/or by moving his or her residual finger vertically withinring 238 to achieve both lateral movement in the direction of arrow Aand vertical movement in the direction of arrow B of distal coupler 216.

FIGS. 8-10 illustrate respective top, front-perspective, andrear-perspective views of another exemplary embodiment of abidirectional and biomechanically driven prosthetic finger 300. In oneembodiment, prosthetic finger 300 may include an eccentric MCP pivot 302configured to attach to a user's hand via a hand strap (not shown)adapted to attach about a back of a user's hand or via any otherappropriate attachment mechanism. MCP pivot 302 may include an anchorplate 306 designed to align with a corresponding residual finger of theuser. In one embodiment, anchor plate 306 may be mounted directly uponthe hand strap via any reasonable and/or appropriate means (e.g., sewn,riveted, adhered etc.). In another embodiment, the hand strap and anchorplate 306 may be molded or otherwise manufactured as a single piece.

MCP pivot 302 may also include a frame 310. At its proximal end, frame310 may be rotationally coupled with anchor plate 306 via anarticulation joint 312 adapted for positioning above/over a select oneof the user's MCP joints. Articulation joint 312 may be a pin, a screw,or any other appropriate fastener that joins anchor plate 306 and frame310 such that frame 310 revolves relative to anchor plate 306 about anaxis parallel to the z axis. At its distal end, frame 310 may berotationally or hingedly coupled with an articulation assembly 314 thatis rotatively coupled between MCP joint 302 and a distal coupler 316.

In this embodiment, articulation assembly 314 may include a two-piece,mirror-image proximal rocker 318. Proximal rocker 318 may include aproximal end 320 and a distal end 322. Proximal end 320 may rotativelycouple with frame 310 via a hinged connection formed of two mirror-imagehinged connections 324.

Articulation assembly 314 may also include an adjustable ring tendon328. Adjustable ring tendon 328 may have a proximal end 330 and a distalend 332. In this embodiment, proximal end 330 of adjustable ring tendon328 may rotatively couple with frame 310 via a hinged connection 334.

In one embodiment, a ring 238 may be disposed upon adjustable ringtendon 328. Ring 338 may be configured to concentrically receive andretain the user's residual finger and may be formed of any appropriatemetal and/or plastic material. As discussed above in relation to rings138 and 238, ring 338 may incorporate a silicone portion or portions forimproved grip, comfort, and serviceability. These silicone portions mayreside along a lower portion of ring 338 and/or they may be incorporatedalong natural pressure points between the finger and ring 338, such asat the top of the proximal phalanx bone.

Ring 338 may be adjusted along the length of adjustable ring tendon 328by sliding ring 338 along a longitudinal adjustment mechanism of tendon328. In this embodiment, the longitudinal adjustment mechanism mayinclude a retention ridge 350 designed to engage with a correspondingclamp portion 352 of ring 338. A positioning screw 354 may intersectclamp portion 352 in a manner that allows positioning screw 354, andthus ring 338, to be tightened against adjustable ring tendon 328 at atarget location 344 along a length of adjustable ring tendon 328. Toadjust, a user may slide ring 338 along the length of adjustable ringtendon 328 before securing ring 338, via positioning screw 354 or anyother appropriate fastener, to tendon 328 at target location 344. Targetlocation 344 may be based on a length of the user's residual finger andresult in an alignment of MCP pivot 302 above/over the user's MCP jointwhen the user's finger is retained within ring 338. In otherembodiments, the longitudinal adjustment mechanism of adjustable ringtendon 328 may be a longitudinal adjustment channel formed within tendon328, and to which ring 338 is secured, or a number of longitudinaladjustment holes disposed along the length of longitudinal adjustmenttendon 328.

In this embodiment of finger assembly 300, articulation assembly 314 mayinclude a four-bar linkage system that connects with distal coupler 316.In further detail, the four-bar linkage system may include four majorinterconnected components that extend from distal end 332 of adjustablering tendon 328 to distal coupler 316. That is, a series of hinges maybe used to secure the primary components of the linkage system in amanner that pivotally suspends a proximal coupler 356 and a distalrocker 358 between distal coupler 316 and adjustable ring tendon 328.Proximal rocker 318 may also by hingedly coupled proximal coupler 356 atits distal end 322.

In one embodiment, the hinges of the four-bar linkage may beparticularly positioned with respect to a pair of axes detailed in FIGS.8-10. More specifically, FIG. 8 depicts a centerline, C, that bisectsfinger assembly 300 relative to the y axis, and FIGS. 9-10 show amidline, M, that intersects a first hinged connection 360 and a thirdhinged connection 364, both detailed below, relative to the z axis whenfinger 300 is in an extended position.

Turning to the various rotative connections that form the linkagesystem, proximal coupler 356 may rotatively couple with distal coupler316 via first hinged connection 360, which may include a pair ofparallel pivotal hinges that are symmetric about centerline, C,discussed above in relation to FIG. 8. Each of the pivotal hinges ofhinged connection 360 may provide a pivot point between proximal coupler356 and distal coupler 316 about an axis parallel to the y axis.

At its proximal end, proximal coupler 356 may rotatively couple withadjustable ring tendon 328 via third hinged connection 364. Third hingedconnection 364 may also include a pair of parallel pivotal hinges thatare symmetric about the centerline, C, one located on each side ofassembly 300 such that each provides a pivot point between adjustablering tendon 328 and proximal coupler 356. As discussed above in relationto FIG. 9, the midline, M, intersects hinged connections 360 and 364,and, therefore both first and third hinged connections 360, 364 arelocated directly upon the midline, M, relative to the z axis.

Distal rocker 358 may have opposing distal and proximal ends 368, 370,respectively, that extend between distal coupler 316 and adjustable ringtendon 328. Distal end 368 may rotatively couple with distal coupler 316via a second hinged connection 362 (FIG. 10) located below the midline,M, relative to the z axis. Proximal end 370 may rotatively couple withadjustable ring tendon 328 via a fourth hinged connection 366 locatedabove the midline, M, relative to the z axis. Both second and fourthhinged connections 362 and 366 may include a pair of parallel pivotalhinges that are symmetric about the centerline, C, each providing arespective pivot point between distal rocker 358 and distal coupler316/adjustable ring tendon 328.

To achieve the “suspension” concept discussed above with respect toproximal coupler 356 and distal rocker 358, first and second hingedconnections 360, 362 may align to form a distal coordinated pivot point372 (FIG. 10), which is anchored upon distal coupler 316. Similarly,third and fourth hinged connections 364, 366 may align to form aproximal coordinated pivot point 374 (FIGS. 9-10). While distal rocker358 and proximal coupler 356 do not directly connect with one another,they each directly and pivotally connect with distal coupler 316 andadjustable ring tendon 328 via the distal and proximal coordinated pivotpoints 372, 374, respectively. As a result, distal rocker 358 andproximal coupler 356 are each independently, pivotally suspended betweendistal coupler 316 and adjustable ring tendon 328, such that theyarticulate in coordinated, yet independent, manners relative to oneanother and about numerous axes parallel to the y axis. This associationof distal rocker 358 and proximal coupler 356, without an actual directlink or connection between the two components, allows for complex,realistic vertical articulation motions (e.g., motions within planesparallel to the x-z plane) of distal rocker 358, proximal coupler 356,and distal coupler 316 in response to biomechanical input forces exertedon adjustable ring tendon 328 by the residual finger retained therein.

Embodiments of any one or more of the first, second, third, and/orfourth hinged connections 360, 362, 364, 366 may be outfitted withhard-stops to prevent hyperextension of finger 300 during operation.Mechanical hard-stops may have any appropriate size, shape, and/orconfiguration.

Distal coupler 316 may include a tip pad 346. Tip pad 346 may be formedfrom a soft-textured silicone or other material that mimics the textureof a real finger and with gripping and provides a softer touch. Oneembodiment of distal coupler 316 may also include a nail 317, whichmimics a natural edged fingernail that may provide scratching andpeeling functionalities as well as assist with fine-object manipulation.

Like articulation assemblies 114, 214 of respective prosthetic finger100, 200, discussed above, articulation assembly 314 is designed forbidirectional articulation. Specifically, assembly 314 and distalcoupler 316 rotate laterally relative to the hand via articulation joint312 of MCP pivot 302, providing prosthetic finger 300 with a firstdirection of movement about an axis parallel to the z axis and within aplane parallel to the x-y plane. This lateral movement is denoted byarrow A, shown in FIG. 8.

Vertical movement within planes parallel to the x-z plane is denoted byarrow B of FIG. 9. Specifically, hinged connections 324 and 334, whichrotatively couple articulation assembly 314 with frame 310 of MCP pivot302, as well as distal and proximal coordinated pivot points 372, 374,which indirectly and rotatively couple adjustable ring tendon 328 withdistal coupler 316, provide multiple rotational connections for movementabout numerous axes parallel to the y axis and within planes parallel tothe x-z plane. As a result, the user may achieve more lifelike movementsof distal coupler 316 that emulate the natural articulation of a fingerby moving his or her residual finger laterally (e.g., adducting and/orabducting the residual finger) within ring 238, and/or by moving his orher residual finger vertically within ring 238 to achieve both lateraland vertical articulation of distal coupler 216.

FIGS. 12-14 illustrate respective top, front-perspective, andrear-perspective views of one embodiment of a bidirectionalbiomechanically driven prosthetic finger 400. In this embodiment,prosthetic finger assembly 400 may include components that are identicalto finger 300, as identified by like reference numbers, and furtherincorporate a multiple-finger ring 438. Multiple-finger ring 438 mayattach to adjustable ring tendon 328 via clamp portion 352 adjusted totarget location 344, similar to the adjustment mechanism for finger 300,discussed above in relation to FIGS. 8-10. Rather than a single ringadapted to receive and retain the user's residual finger, however,multiple-finger ring 438 may extend laterally to encompass at least oneadditional finger located adjacent to the user's residual finger. As aresult, and in the embodiment shown in FIGS. 12-14, the user may slidehis or her residual finger as well as an adjacent finger withinmultiple-finger ring 438. This allows the user to employ the adjacentfinger, which may be stronger, more functionally adept, and lesssensitive than the residual finger, to actuate lateral motion throughMCP pivot 302 and vertical motion through articulation assembly 314.

In this embodiment, multiple-finger ring 438 includes two abutting rings439 and 441. Alternative embodiments may include any number and/or anylocation of rings as appropriate and/or desired to take advantage of theforce and dexterity offered by the user's fingers adjacent to theresidual finger, or, in other words, to take advantage of the user'sremaining fingers, whether abutting or spaced apart from the residualfinger.

Additional multiple-finger ring embodiments may also incorporate anoffset between the ring adapted to receive the residual finger (e.g.,ring 439) and the ring or rings adapted to receive adjacent fingers(e.g., ring 441). This offset may allow rings adapted for adjacentfingers to fit finger segments that do not lie adjacent to (i.e., thatlie proximal or distal to) the target location 344. This positioningallows adjacent fingers to provide actuation force from a positionoffset from target location 344, which provides an optionally longer orshorter lever arm to impact the force translated from the adjacentfinger to adjustable ring tendon 328, and from there, through theremainder of articulation assembly 314.

Embodiments of bidirectional biomechanical prosthetic finger 100, 200,300, 400 are custom designed and individually fitted to accommodate avariety of differing user conditions. In this regard, each finger 100,200, 300, 400 may be custom manufactured to fit a particular patient oruser, providing both custom functionality as well as a mechanical matchto the anatomical joint articulation of the user. Design considerationsinclude a number and physiology of joints to be stabilized and othercharacteristics specific to the individual end user.

To further provide better aesthetics, embodiments of prosthetic finger100, 200, 300, 400 may be coated with films and/or colorings matched tothe user's skin tone/color. An additive manufacturing process (i.e., 3Dprinting) facilitates this ability to customize the intricacies of theprosthetic design in order to optimize prosthetic finger 100, 200, 300,400 for each patient.

For additional functionality, embodiments of prosthetic finger 100, 200,300, 400 may incorporate a touchscreen mechanism (not shown) to allowthe user to use prosthetic finger 100, 200, 300, 400 to operatecapacitive touchscreens, which react to the body's natural current. Thetouchscreen mechanism allows the user to direct his or her own bodycurrent through distal coupler 116, 216, 316.

Embodiments of prosthetic finger 100, 200, 300, 400 may be formed of anysuitable structural material that is non-irritating to human skin andallows the user to operate the brace with comfort and confidence.Exemplary materials include titanium, stainless steel, aluminum,silicone, carbon fiber, nylon, plastic/polymer, wood, rubber, gold,silver, tungsten, flex cable, neoprene, or any other suitable material.In one embodiment, components of prosthetic finger 100, 200, 300, 400are 3D printed from Duraform EX polymer material.

Using biocompatible materials, various embodiments of prosthetic finger100, 200, 300, 400 may be applied as an orthopedic implant that may besurgically implanted into a user's finger. This option may be appliedfor users having injuries that have crushed their finger bones withoutthe ability to heal or be repaired. In these situations, implantableembodiments of biomechanical finger 100, 200, 300, 400 are able to takethe place of the user's original bones without the need for amputation.

Once finger 100, 200, 300, 400 (adjusted or otherwise) is in place, theuser may utilize his or her natural finger movements. The rotativelycoupled components of finger 100, 200, 300, 400 will articulate usingthe same cognitive process that was previously utilized for the originalfinger. If a user wears multiple prosthetic fingers 100, 200, 300, 400,each may be individually operated.

Embodiments of the finger assembly 100, 200, 300, 400 described aboveexhibit numerous unique characteristics and provide a variety of medicalbenefits. An individual's unique physiology and lifestyle patternsdictate the function and performance expected of his or her hands. Usingembodiments of the prosthetic finger assembly described herein, patientsmay regain independent control of their hands, whether at work or atplay. Each device is custom designed, manufactured for a specificindividual, and incorporates features that allow for further fine-tuningand adjustment of fit to account for post-manufacturing fluctuations(e.g., shims), enabling the device to fit the user in a manner thatallows for a biomechanically driven, low profile, lightweight, highlyfunctioning return to the user's everyday activities, no matter whatthose activities might entail. A few examples include typing, playingthe piano or another instrument, woodworking, and much more.

Embodiments of the biomechanical finger assembly described above arebody powered, accommodate bidirectional movement, and feature linkedcomponents that articulate when the user simply moves his or herresidual finger and/or adjacent fingers. Beyond allowing for a simple,elegant, and streamlined design that offers strength in the lowestpossible profile design, employing the user's own biomechanics to driveembodiments of finger 100, 200, 300, 400 provides a host of medicalbenefits to the user, including reduced swelling of and increasedcirculation to the residual finger and the hand as a whole, supportinghealthy joints in the injured and adjacent fingers.

FIG. 11 provides a flow chart depicting an exemplary method 500 ofoperation the prosthetic finger assemblies discussed above. For the sakeof clarity, method 500 will be described in relation to finger assembly300, but it should be understood that method 500 applies equally to anyprosthetic finger embodiment. Method 500 may begin with assessing alength (502) of the user's residual finger. Based on this length, ring338 may be adjusted (504) along adjustable ring tendon 328 to targetlocation 344 and secured (506) in place along the longitudinaladjustment mechanism of adjustable ring tendon 328. As discussed above,the longitudinal adjustment mechanism may take any appropriate size,shape, type, and/or configuration that allows ring 338 to be secured ata location along the length of adjustable ring tendon 328 that alignsMCP pivot 302 with the MCP joint of the user.

Once ring 338 has been adjusted and secured, finger assembly 300 may beslid onto the user's residual finger (508), such that ring 338 encirclesand retains the residual finger adjacent to target location 344 and theMCP pivot aligns with the user's MCP joint. If MCP pivot 302 does notalign with the user MCP joint once ring 338 is fitted about the residualfinger, then prosthetic finger 300 may be removed (510) for readjustment(504). If MCP pivot 302 aligns above the user's MCP joint once ring 338is fitted about the residual finger, then the user may bidirectionallyarticulate (512) prosthetic finger 300 by moving his or her residualfinger vertically (514) within ring 338, thereby causing articulationassembly 314 and distal coupler 316 to articulate within a planeparallel to the x-z plane and about a number of axes parallel to the yaxis, and by moving his or her residual finger laterally (516) withinring 338, thereby causing articulation assembly 314 and distal coupler316 to revolve about MCP pivot 302 within a plane parallel to the x-yplane and about an axis parallel to the z axis.

Although the above embodiments have been described in language that isspecific to certain structures, elements, compositions, andmethodological steps, it is to be understood that the technology definedin the appended claims is not necessarily limited to the specificstructures, elements, compositions and/or steps described. Rather, thespecific aspects and steps are described as forms of implementing theclaimed technology. Since many embodiments of the technology can bepracticed without departing from the spirit and scope of the invention,the invention resides in the claims hereinafter appended.

What is claimed is:
 1. A bidirectional biomechanical finger assembly fora user's residual finger, comprising: a metacarpophalangeal (MCP) pivot;a distal coupler; and an articulation assembly rotatively coupledbetween the MCP pivot and the distal coupler, the articulation assemblycomprising: an adjustable ring tendon having a distal end, a proximalend, and a longitudinal adjustment mechanism disposed therebetween, theproximal end rotatively coupled with the MCP pivot; a multiple-fingerring configured to receive and retain the residual finger and at leastone adjacent finger, the multiple-finger ring selectively disposed uponthe adjustable ring tendon at a target location along the longitudinaladjustment mechanism; a proximal coupler; and a distal rocker, wherein:the proximal coupler and the distal rocker are rotatively suspendedbetween a proximal coordinated pivot point anchored upon the adjustablering tendon and a distal coordinated pivot point anchored upon thedistal coupler; the articulation assembly is configured to utilizevertical movements of at least one of the residual finger and the atleast one adjacent finger within the multiple-finger ring to articulatethe distal coupler within a plane parallel to an x-z plane and about oneor more axes parallel to a y axis; and the MCP pivot is configured toutilize lateral movements of at least one of the residual finger and theat least one adjacent finger within the multiple-finger ring toarticulate the distal coupler within a plane parallel to an x-y planeand about an axis parallel to a z axis.
 2. The bidirectionalbiomechanical finger assembly of claim 1, wherein the multiple-fingerring comprises two abutting rings.
 3. The bidirectional biomechanicalfinger assembly of claim 2, wherein the articulation assembly furthercomprises a proximal rocker having a distal end and a proximal end, thedistal end of the proximal rocker pivotally attached to the proximalcoupler and the proximal end of the proximal rocker pivotally attachedto the MCP pivot.
 4. The bidirectional biomechanical finger assembly ofclaim 3, further comprising a hand strap configured for attachment to ahand of the user, wherein: the MCP pivot is secured to the hand strap;and when the hand strap is attached to the hand of the user, the MCPpivot aligns with an MCP joint of the user.
 5. The bidirectionalbiomechanical finger assembly of claim 1, wherein the target location ofthe multiple-finger ring upon the adjustable ring tendon comprises alocation along the longitudinal adjustment mechanism that causes the MCPpivot to align with an MCP joint of the user when the residual fingerand the at least one adjacent finger are retained within themultiple-finger ring.
 6. The bidirectional biomechanical finger assemblyof claim 1, wherein the longitudinal adjustment mechanism of theadjustable ring tendon comprises a retention ridge configured to engagewith a clamp portion of the multiple-finger ring.
 7. The bidirectionalbiomechanical finger assembly of claim 1, wherein the MCP pivotcomprises: an anchor plate; a frame having a proximal end and a distalend; and an articulation joint, wherein the distal end of the frame isrotatively coupled to the articulation assembly via one or more hingedconnections configured to rotate about the one or more axes parallel tothe y axis, and the proximal end of the frame is rotatively coupled tothe anchor plate via the articulation joint configured to rotate aboutthe axis parallel to the z axis.
 8. The bidirectional biomechanicalfinger assembly of claim 7, wherein: the distal coordinated pivot pointcomprises a first hinged connection between the proximal coupler and thedistal coupler and a second hinged connection between the distal rockerand the distal coupler; and the proximal coordinated pivot pointcomprises a third hinged connection between the proximal coupler and theadjustable ring tendon and a fourth hinged connection between the distalrocker and the adjustable ring tendon.
 9. The bidirectionalbiomechanical finger assembly of claim 8, wherein: the first hingedconnection between the proximal coupler and the distal coupler and thethird hinged connection between the proximal coupler and the adjustablering tendon define a midline relative to the z axis; the second hingedconnection between the distal rocker and the distal coupler is locatedbelow the midline; and the fourth hinged connection between the distalrocker and the adjustable ring tendon is located above the midline, suchthat a relative rotational motion between the adjustable ring tendon andthe distal rocker causes a relative rotational motion between theproximal coupler and the distal coupler to emulate a finger's naturalarticulation within the plane parallel to the x-z plane.
 10. Abidirectional biomechanically driven prosthetic finger, comprising: ametacarpophalangeal (MCP) pivot for attachment to a hand of a user, theMCP pivot having an articulation joint configured to rotate the MCPpivot relative to the hand within a plane parallel to an x-y plane andabout an axis parallel to a z axis; a distal coupler; an articulationassembly rotatively coupled between the MCP pivot and the distalcoupler, the articulation assembly configured to articulate relative tothe hand within a plane parallel to an x-z plane and about one or moreaxes parallel to a y axis, the articulation assembly comprising: aproximal coupler rotatively coupled with the distal coupler via a firsthinged connection; an adjustable ring tendon having a proximal end, adistal end, and a multiple-finger ring disposed thereon, themultiple-finger ring configured to anchor onto a residual finger and atleast one adjacent finger of the user and slidably adjustable betweenthe proximal and distal ends of the adjustable ring tendon; and a distalrocker extending between the distal coupler and the adjustable ringtendon, the distal rocker having a distal end and a proximal end,wherein: the adjustable ring tendon is rotatively coupled with theproximal coupler via a third hinged connection; the first and thirdhinged connections define a midline relative to the z axis; the distalend of the distal rocker rotatively couples with the distal coupler viaa second hinged connection located below the midline; and the proximalend of the distal rocker rotatively couples with the adjustable ringtendon via a fourth hinged connection located above the midline.
 11. Thebidirectional biomechanically driven prosthetic finger of claim 10,wherein the MCP pivot comprises: an anchor plate; a frame havingproximal and distal ends, the proximal end of the frame disposed uponthe anchor plate, wherein the articulation joint pins the anchor plateand the frame together such that they revolve relative to one anotherabout the axis parallel to the z axis.
 12. The bidirectionalbiomechanically driven prosthetic finger of claim 11, further comprisinga hand strap configured to attach about a hand of the user, wherein theanchor plate of the MCP pivot is secured to the hand strap.
 13. Thebidirectional biomechanically driven prosthetic finger of claim 11,wherein the adjustable ring tendon includes a longitudinal adjustmentmechanism for slidably adjusting the multiple-finger ring to a targetlocation between the proximal and distal ends of the adjustable ringtendon.
 14. The bidirectional biomechanically driven prosthetic fingerof claim 13, wherein the longitudinal adjustment mechanism comprises aretention ridge configured to engage with a clamp portion of themultiple-finger ring.
 15. The bidirectional biomechanically drivenprosthetic finger of claim 13, wherein the target location comprises alocation that aligns the MCP pivot with an MCP joint of the user whenthe multiple-finger ring is anchored about the residual finger and theat least one adjacent finger.
 16. The bidirectional biomechanicallydriven prosthetic finger of claim 10, wherein the multiple-finger ringcomprises at least two rings, and wherein the two rings abut oneanother.
 17. The bidirectional biomechanically driven prosthetic fingerof claim 10, wherein the proximal coupler and the distal rocker lack adirect connection.
 18. A method of biomechanically operating abidirectional prosthetic finger having a hand strap, ametacarpophalangeal (MCP) pivot affixed to the hand strap, a distalcoupler, and an adjustable articulation assembly rotatively coupledbetween the MCP pivot and the distal coupler, the adjustablearticulation assembly including a multiple-finger ring configured toreceive a residual finger and at least one adjacent finger of a user'shand, the method comprising: assessing a length of the residual finger;adjusting the multiple-finger ring to a target location along theadjustable articulation assembly, the target location based on thelength of the residual finger; securing the ring at the target location;sliding the prosthetic finger onto the residual finger such that themultiple-finger ring encircles the residual finger and the at least oneadjacent finger, and the MCP pivot aligns with an MCP joint of the user;securing the hand strap about the hand; moving one of the residualfinger and the at least one adjacent finger vertically within themultiple-finger ring, thereby causing the adjustable articulationassembly together with the distal coupler to articulate within a planeparallel to an x-z plane and about one or more axes parallel to a y axisin a manner that emulates a finger's natural articulation; and movingone of the residual finger and the at least one adjacent fingerlaterally within the ring, thereby causing the MCP pivot to rotate aboutan axis parallel to a z axis within a plane parallel to an x-y plane,such that the articulation assembly together with the distal couplerabduct away from a midline of the hand and adduct toward the midline ofthe hand.
 19. The method of claim 18, wherein the adjustablearticulation assembly comprises: an adjustable ring tendon having alongitudinal adjustment mechanism with a proximal end and a distal end,the target location disposed therebetween; a proximal coupler extendingbetween the distal coupler and the adjustable ring tendon, the proximalcoupler having a distal end and a proximal end, wherein: the distal endof the proximal coupler is rotatively coupled with the distal couplervia a first hinged connection; the proximal end of the proximal coupleris rotatively coupled with the adjustable ring tendon via a third hingedconnection; and the first and third hinged connections define a midlinerelative to a z axis; and a distal rocker extending between the distalcoupler and the adjustable ring tendon, the distal rocker having adistal end and a proximal end, wherein: the distal end of the distalrocker is rotatively coupled with the distal coupler via a second hingedconnection located below the midline; and the proximal end of the distalrocker is rotatively coupled with the adjustable ring tendon via afourth hinged connection located above the midline.
 20. The method ofclaim 19, wherein the adjusting the multiple-finger ring to the targetlocation comprises adjusting the multiple-finger ring to a locationbetween the proximal and distal ends of the longitudinal adjustmentmechanism that causes the MCP pivot to align with an MCP joint of theuser when the multiple-finger ring is anchored about the residual fingerand the at least one adjacent finger.